Pneumatic door operator



Feb. 1, 1966 R. E. DIMMITT ETAL 3,232,600

PNEUMATIC DOOR OPERATOR 2 Sheets-Sheet 1 Filed Dec. 16, 1963 5 T nmn M NL VWMWM WD 0: & i D 3 y LO QRM AY M Y c B A T TORNE YS Feb. 1, 1966 R. E. DIMMITT ETAL 3,232,600

PNEUMATIC DOOR OPERATOR Filed D60. 16, 1963 2 Sheets-Sheet 2 INVENTORS ROBERT E. DIMMITT CHARLES KESSNER RAYMOND RIDGLEY Rig *2 ATTORNEYS United States Patent 3,232,600 PNEUMATIC DOOR OPERATOR Robert Ernest Dimmitt, Charles Kessner, and Raymond Ridgley, Seattle, Wash., assignors to Dor-West, Inc., Seattle, Wash., a corporation of Washington Filed Dec. 16, 1963, Ser. No. 330,883 18 Claims. (Cl. 26839) This invention relates to a pneumatic operator, and particularly an operator for use in opening and closing doors. The invention is especially applicable to a door of the sliding character, and as one of its object aims to provide a pneumatic operator which occupies an unusually compact space and thus admits of being housed in a recess of small compass located overhead to the sliding door and such as is commonly provided to accommodate an overhead track from which the sliding door is hung.

It is a further particular object of the invention to provide a pneumatic operator which is engineered to produce a thrust force having a high potential at the initiation of a door-opening operation so that the door is made quickopening, and dropping to a low level as the door approaches a bumper stop at the outer extreme of such opening travel so that the door will not rebound as it strikes such stop.

The invention has the still further and important object of providing a pneumatic door operator which can be easily and quickly adjusted to give the door any de sired speed in its opening and closing movements.

The foregoing and other objects and advantages in view will appear and be understood in the course of the following description and claims, the invention consisting in the novel construction and in the adaptation and combination of parts hereinafter described and claimed.

In the accompanying drawings:

FIGURE 1 is a fragmentary longitudinal vertical sectional view illustrating an automatic entrance having its doors actuated by a pneumatic operator embodying teachings of the present invention, the section line being shown at 11 of FIG. 2.

FIG. 2 is a fragmentary transverse vertical sectional view drawn to an enlarged scale on line 22 of FIG. 1; and

FIG. 3 is a diagrammatic view showing the circuitry of the pneumatic operator.

Referring to said drawings, a door of the type for which the pneumatic operator of the present invention is particularly designed is denoted generally by the numeral 10, and is hung from an overhead track for slide motion in a direction transverse to an entrance opening from a normal position closing said entrance opening into and out of a side pocket 11. There may be only one pocket accommodating a single door which extends the full width of the opening, or (as here illustrated) two pockets may be provided, one at each of the two sides to accommodate a respective one of two in-line doors which move oppositely in unison and individually close one-half the opening.

A rib-type rail 12 serves as the overhead track and is concealed within a head recess 13, being supported by brackets 14 and 15, respectively, from both end walls and one side wall of the recess to occupy a position median to the width of the recess. Each door includes a header section 16 and has a repective carriage 17 surmounting the 3232,69 Patented Feb. 1, 1966 header section at each of the two ends. Wheels 18 journalled from the upper ends of the carriages track upon the rail 12. Each carriage, in addition to the wheels 18, also supports a nonrise roller 20.

Connection between the two doors, so that powered operation of one causes the other door to move oppositely in unison therewith, is provided by a cable which is trained at each of the two ends of the recess about a respective pulley, as 22 and 23, and has an upper run 24 anchored to one of the two carriages of one door and a lower run 25 anchored to one of the two carriages of the other door. The two runs of the cable occupy a vertical plane spaced from and paralleling the rail 12 at the side thereof opposite the mounting bracket 15. For the anchoring of the cable to the concerned carriages, each such carriage has a laterally extending cared bracket, as 26 and 27, fixedly secured thereto. Bracket 26 is prolonged laterally beyond the bracket 27. The pneumatic operator of the present invention is housed within the recess 13 along the side wall which lies opposite the mounting bracket 15, being supported by suitable brackets which are attached to said side Wall. A rod 28 connects said operator with the prolongation to impart reciprocal motion to the latter along the travel path prescribed by the rail.

Provided by the operator are a power air cylinder 30 .and a check air cylinder 31 lying one alongside the other and providing identical bore and stroke for respective double-acting pistons. The pistons have their rods 32 and 33 coupled, so as to move in concert, by an interlock 34. Rod 28 is rooted to the interlock. The check cylinder exhausts air through needle valves which are fitted with silencers 35, and has each of its two ends valved, as at 36, for free inflow of air.

A reservoir 37 connects by an air line 33 with the after end of the power cylinder, and provided in this line is a solenoid valve 39. This is a 3-way valve acting in its normal de-energized position to isolate the reservoir and establish a dumping connection to atmosphere from the after end of the power cylinder. A connection 40 leads to the reservoir 37 from a pressure source of air supply 41 which maintains a predetermined pressure level by means of a motor-driven pump 42. in the connection 40 is a strainer 43 and three valves 44, 45 and 46. Valve 44 lies to the front of the strainer and is a stop valve for cutting oil the air supply when servicing the system. Valve 45 lies behind the strainer and is a pressure-regulating valve. This valve admits of being set to any pressure level between 0 and p.s.i. and acts to regulate the air pressure for a desired door-opening speed. Valve 46 lies behind the valve 45 and is a needle valve adjustable for rate of flow of the pressure air fed to the reservoir.

A connection 47 to the forward end of the power cylinder 30 joins the feed line 40 at a point spaced to the front of the needle valve 46, or which is to say between said needle valve and the supply source 41. In this connection, in order, is a pressure-regulating valve 48- having a range of 5 to 50 psi. and a solenoid valve 50. Like the solenoid valve 39, the solenoid valve 50 is a 3-way valve with a dump port to atmosphere but normally main tains an open condition from the supply source to the power cylinder, isolating the source from the front end of the cylinder and coincidentally dumping pressure air from the latter when the solenoid is energized.

Characteristics salient to the present operator is that the reservoir 37 has a capacity substantially less than that of the power cylinder (say 1 to 3 /2), and a choked charging flow (say Mr that of line 38) such that the opening air volume and the pressure are kept in direct proportion sufficient only to give the door controlled operation without allowing full air pressure to suddenly exert its full force on a re-cycle, which would make the reverse force hard to control.

It will be understood that the solenoid valve 50, being normally open, supplies pressure air to the forward end of the power cylinder so that the doors normally are held in a closed position. A switch A which is or may be actuated automatically by a person traversing a given traffic zone, as by stepping upon an electric carpet in course of approaching the entrance opening from either direction, operates the solenoid valves 50 and 39. Pressure air is then supplied from the reservoir to the rear end of the power cylinder coincident with a dumping of the pressure air present in the forward end of such cylinder. The doors have a high-pressure starting impulse as the reservoir unloads into the power cylinder, the supplied volume of air progressively diminishing in that the reservoir recharges only at the choked rate of flow prescribed by the needle valve 46. The doors, striking a bumper stop (not shown) at the outer extreme of their opening travel, are freed of the tendency to rebound. As the trafiic zone becomes freed of trafiic, a responsive tie-energizing of the controlling relay B for the solenoids acts to open valve 54 and close valve 39, whereupon pressure air enters the forward end of the power cylinder and dumps from the rear end, which returns the doors to their closed position. Cylinder 31 performs a checking function in both strokes of the power piston. Valve .6 permits a choked flow of air to be charged to the reservoir during both the door-opening and the doorclosing strokes of the power piston. It is desirable that the door have a closing speed such as will permit the reservoir to receive a full pressure charge within the period required for the power piston to complete its door-closing stroke of reciprocation.

It is thought that the invention and the manner of its operation will have been clearly understood from the foregoing detailed description of our now-preferred illustrated embodiment. Changes in the details of construction may be resorted to without departing from the spirit of the invention and it is accordingly our intention that no limitations be implied and that the hereto annexed claims be given the broadest interpretation to which the employed language fairly admits.

What we claim is:

1. A pneumatic operator for moving an object along an establ shed travel path comprising a source of pressure air supply, a reservoir, a power air cylinder, a piston working in said power cylinder, operative connection between the piston and the object acting to move the object along said travel path by movement of the piston in one power stroke of its reciprocatory action, a connection between the reservoir and the power cylinder fitted with a normally closed valve, means for opening said valve, and a connection from the supply source to the reservoir having a flow capacity substantially less than the flow capacity of said opened valve, the air capacity of the reservoir being less than that of the power cylinder.

2. A'pneumatic operator according to claim 1 in which the capacity of the reservoir is less than one-third that of the powercylinder.

3. A pneumatic operator according to claim 1 having means interconnected with the piston of said power cylinder and made to dampen the powered motion which the delivered pressure air imparts thereto.

4. A pneumatic operator according to claim 3 in which the motion-dampening means comprises a second piston working in a check-type air cylinder.

5. A pneumatic operator according to claim 1 having means adjustable to different settings for providing seleci tively variable ratios as between the flow capacities of the two connections which lead one to and the other from the reservoir.

6. A pneumatic operator according to claim 1 having a pressure-regulating valve in the connection which leads from the supply source to the reservoir.

7. A pneumatic operator according to claim 1 in which the object to be moved is a door hung for sliding movement from an overhead track occupying a recess above the door, and wherein the recited components of the operator together with a power-driven pump connected with the supply source for maintaining the pressure of the source air above a predetermined level are housed within said overhead recess.

8. The pneumatic operator of claim 7 in which the power cylinder and a cylinder serving as the reservoir, together with a third cylinder operatively connected with the piston of the power cylinder to perform a checking function therefor, lie in positions paralleling the track one above another to one side of the track.

9. In combination with a sliding door, a pneumatic operator for opening said door comprising: a doubleacting air cylinder, a piston working in said cylinder, operative connection between said piston and the door acting to open the door by powered motion of the piston in one stroke of reciprocation and to close the door by powered motion of the piston in its opposite stroke of reciprocation, a source of pressure air supply, a reservoir, a main air-flow line leading from the source, three airflow lines comprised of a #1 line branching oil the main line and extending therefrom to the end of the cylinder responsible for moving the piston in its door-closing travel, a #2 line branching off the main line and extending therefrom to the reservoir, and a #3 line extending between the reservoir and the other end of the cylinder, the #2 line having a flow capacity substantially choked by comparison with that of the #3 line, valve means in the #1 line movable from a normal position connecting the supply source with the concerned end of the cylinder into and out of a position which isolates said supply source and coincidently dumps air from the concerned end of the cylinder, and valve means in the #3 line movable from a normal position which isolates the reservoir from the concerned end of the cylinder, while coincidently dumping air from said concerned end, into and out of a position which closes the dump opening and connects said reservoir with said concerned end of the cylinder.

10. A pneumatic operator according to claim 9 'in which a valve manually adjustable to selected flow capacities serves as the choking instrument for the #2 line.

11. A pneumatic operator according to claim 9 in which each of the two valve means comprises a 3-way solenoid-operated valve.

12. A pneumatic operator according to claim 11 in which the solenoids for the valves are energized by current drawn from electric circuits controlled automatically by the act of a person entering and leaving a given trafilc zone associated with the door.

13. A door operator according to claim 9 providing a checking cylinder sized in correspondence with the power cylinder and occupying a paralleling position alongside the latter, and having a piston working in said checking cylinder and operatively connected with the power cylinder so as to move in concert therewith.

14. A pneumatic operator according to claim 13 in which a track serving as a slide-way for carriages from which the door is hung occupies a recess above the door, and wherein the recited components of the operator together with a pump holding the pressure of thersource above a predetermined level are housed within said overhead recess.

15. A pneumatic operator according 'to claim 9 in which the capacity of the reservoir as compared with 5 6 that of the cylinder is in the ratio, approximately, of 18. Apneumatic operator according to claim 17 having Ito 3 a pressure-regulating valve in the main air-flow line.

16. A pneumatic operator according to claim 15 in which the choking of the #2 line provides a flow capacity approximately one-fourth that of the #3 line. 5 2 810 571 Z I PtA'IlENTS 268 34 17. A pneumatic operator according to claim 9 having 2853292 9/1958 g g g e a 268:66 a pressure regulating valve in the #1 line located upstream from said valve means. HARRISON R. MOSELEY, Primary Examiner.

References Cited by the Examiner 

1. A PNEUMATIC OPERATOR FOR MOVING AN OBJECT ALONG AN ESTABLISHED TRAVEL PATH COMPRISING A SOURCE OF PRESSURE AIR SUPPLY, A RESERVOIR, A POWER AIR CYLINDER, A PISTON WORKING IN SAID POWER CYLINDER, OPERATIVE CONNECTION BETWEEN THE PISTON AND THE OBJECT ACTING TO MOVE THE OBJECT ALONG SAID TRAVEL PATH BY MOVEMENT OF THE PISTON IN ONE POWER STROKE OF ITS RECIPROCATORY ACTION, A CONNECTION BETWEEN THE RESERVOIR AND THE POWER CYLINDER FITTED WITH A NORMALLY CLOSED VALVE, MEANS FOR OPENING SAID VALVE, AND A CONNECTION FROM THE SUPPLY SOURCE TO THE RESERVOIR HAVING A FLOW CAPACITY SUBSTANTIALLY LESS THAN THE FLOW CAPACITY OF SAID OPENED VALVE, THE AIR CAPACITY OF RESERVOIR BEING LESS THAN THAT OF THE POWER CYLINDER. 